Banks and mortgage servicers that made phony Federal Housing Administration insurance claims to the feds could owe as much as $500 million in penalties and damages — for New York State alone.

That’s the bombshell allegation by Lynn Szymoniak — the forensic document expert who blew the lid off the robosigning scandal in 2010 — and her legal team in a federal lawsuit alleging violations of the False Claims Act.

The defendants are Deutsche Bank, Bank of NY Mellon, US Bank and HSBC, plus American Home Mortgage Servicing, Saxon, Lender Processing Services and DocX.

Szymoniak also alleges the lenders charged the Department of Housing and Urban Development for false documents. FHA is part of HUD. The price tag is an estimated $900,000 for production of false documents for FHA loans in New York.

“Essentially HUD is paying for documents to defraud itself, is our claim,” Szymoniak told The Post.

“Anybody who has been charged a fee by a bank for insufficient funds in their account knows banks have absolutely no mercy on individuals,” said Szymoniak’s attorney Reuben Guttman of Grant & Eisenhofer. “Here banks en masse used phony documents to procure insurance money from the federal government, and should be penalized heavily.”

In 2012, as part of the $25 billion national mortgage settlement, Chase, Wells Fargo, Ally, Bank of America and Citi settled part of Szymoniak’s suit for $95 million without admitting wrongdoing. The federal government took part in that case.

The federal government declined to intervene in the current case, however. Sources told The Post that the US Attorney’s office wanted to, but the Department of Justice, which has final say, wasn’t interested.

Szymoniak is awaiting a ruling by Judge Joseph Anderson on whether she can press ahead as a private citizen.

Bank of NY Mellon, HUD and the U.S. Attorneys office declined to comment, as did the other banks and servicers.